1 files changed, 53 insertions, 6 deletions

diff --git a/drivers/dma/ti/edma.c b/drivers/dma/ti/edma.c
index 54fd981e3db5..0ecfc2e1d798 100644
--- a/drivers/dma/ti/edma.c
+++ b/drivers/dma/ti/edma.c
@@ -260,6 +260,13 @@ struct edma_cc {
 	 */
 	unsigned long *slot_inuse;
 
+	/*
+	 * For tracking reserved channels used by DSP.
+	 * If the bit is cleared, the channel is allocated to be used by DSP
+	 * and Linux must not touch it.
+	 */
+	unsigned long *channels_mask;
+
 	struct dma_device		dma_slave;
 	struct dma_device		*dma_memcpy;
 	struct edma_chan		*slave_chans;
@@ -716,6 +723,12 @@ static int edma_alloc_channel(struct edma_chan *echan,
 	struct edma_cc *ecc = echan->ecc;
 	int channel = EDMA_CHAN_SLOT(echan->ch_num);
 
+	if (!test_bit(echan->ch_num, ecc->channels_mask)) {
+		dev_err(ecc->dev, "Channel%d is reserved, can not be used!\n",
+			echan->ch_num);
+		return -EINVAL;
+	}
+
 	/* ensure access through shadow region 0 */
 	edma_or_array2(ecc, EDMA_DRAE, 0, EDMA_REG_ARRAY_INDEX(channel),
 		       EDMA_CHANNEL_BIT(channel));
@@ -2249,7 +2262,7 @@ static int edma_probe(struct platform_device *pdev)
 {
 	struct edma_soc_info	*info = pdev->dev.platform_data;
 	s8			(*queue_priority_mapping)[2];
-	const s16		(*rsv_slots)[2];
+	const s16		(*reserved)[2];
 	int			i, irq;
 	char			*irq_name;
 	struct resource		*mem;
@@ -2329,15 +2342,32 @@ static int edma_probe(struct platform_device *pdev)
 	if (!ecc->slot_inuse)
 		return -ENOMEM;
 
+	ecc->channels_mask = devm_kcalloc(dev,
+					   BITS_TO_LONGS(ecc->num_channels),
+					   sizeof(unsigned long), GFP_KERNEL);
+	if (!ecc->channels_mask)
+		return -ENOMEM;
+
+	/* Mark all channels available initially */
+	bitmap_fill(ecc->channels_mask, ecc->num_channels);
+
 	ecc->default_queue = info->default_queue;
 
 	if (info->rsv) {
 		/* Set the reserved slots in inuse list */
-		rsv_slots = info->rsv->rsv_slots;
-		if (rsv_slots) {
-			for (i = 0; rsv_slots[i][0] != -1; i++)
-				bitmap_set(ecc->slot_inuse, rsv_slots[i][0],
-					   rsv_slots[i][1]);
+		reserved = info->rsv->rsv_slots;
+		if (reserved) {
+			for (i = 0; reserved[i][0] != -1; i++)
+				bitmap_set(ecc->slot_inuse, reserved[i][0],
+					   reserved[i][1]);
+		}
+
+		/* Clear channels not usable for Linux */
+		reserved = info->rsv->rsv_chans;
+		if (reserved) {
+			for (i = 0; reserved[i][0] != -1; i++)
+				bitmap_clear(ecc->channels_mask, reserved[i][0],
+					     reserved[i][1]);
 		}
 	}
 
@@ -2389,6 +2419,7 @@ static int edma_probe(struct platform_device *pdev)
 
 	if (!ecc->legacy_mode) {
 		int lowest_priority = 0;
+		unsigned int array_max;
 		struct of_phandle_args tc_args;
 
 		ecc->tc_list = devm_kcalloc(dev, ecc->num_tc,
@@ -2410,6 +2441,18 @@ static int edma_probe(struct platform_device *pdev)
 				info->default_queue = i;
 			}
 		}
+
+		/* See if we have optional dma-channel-mask array */
+		array_max = DIV_ROUND_UP(ecc->num_channels, BITS_PER_TYPE(u32));
+		ret = of_property_read_variable_u32_array(node,
+						"dma-channel-mask",
+						(u32 *)ecc->channels_mask,
+						1, array_max);
+		if (ret > 0 && ret != array_max)
+			dev_warn(dev, "dma-channel-mask is not complete.\n");
+		else if (ret == -EOVERFLOW || ret == -ENODATA)
+			dev_warn(dev,
+				 "dma-channel-mask is out of range or empty\n");
 	}
 
 	/* Event queue priority mapping */
@@ -2427,6 +2470,10 @@ static int edma_probe(struct platform_device *pdev)
 	edma_dma_init(ecc, legacy_mode);
 
 	for (i = 0; i < ecc->num_channels; i++) {
+		/* Do not touch reserved channels */
+		if (!test_bit(i, ecc->channels_mask))
+			continue;
+
 		/* Assign all channels to the default queue */
 		edma_assign_channel_eventq(&ecc->slave_chans[i],
 					   info->default_queue);